So, I was directed by others here about the Dell RM112 235W 80+ Gold PSU that's been showing up on eBay lately. So I grabbed one. Here's a few pictures of it taken apart.

My plan is to make it usable in a standard ATX PC. First thing that I noticed after opening the box that I didn't expect was that the 24pin connector is not standard. It's about 3/4th the size and it looks like the pins are in a different order. (See first picture) So I guess that's my first step is cutting all the wires and making sure I solder on the new wires to the right ones. The colors seem to all be normal so it shouldn't be too bad. But I will make sure to plug it into an old PC that I don't care about frying to test it out first. If that all works out, I have to see what I can do to fit it into a standard ATX PSU case. I have a spare from a FSP green PSU that died.

I'll report back after I get past these first hurdles and can actually get it up and running. I'll then do some comparisons with my other PSUs. Seasonic SS-300SFD, picoPSU 150 + 200W brick and maybe some others.

I have some questions, I hope to get answers for ::)
Pic1 Is the bigger one a standard ATX connector? According to specs they should have 1 purple wire but on the picture I can see at least 4 or they are using this color instead of red/orange?
Pic2 Those white things are potentiometers for regulating voltages?
Pic3 What does that button do?

There is a dell dimension pin-out too available but this seems to have different wiring and this RM112 coloring seems closer to ATX specs.

I'll report back after I get past these first hurdles and can actually get it up and running. I'll then do some comparisons with my other PSUs. Seasonic SS-300SFD, picoPSU 150 + 200W brick and maybe some others.

That's a nice set of low power/high efficiency PSU you have.

Add me to the list looking forward to your comparison. I'd particularly like to see a test showing the unloaded power draw, by shorting the green and any black on the 20/24 pin ATX connector. So far in my sample of PSU I've seen a spread of 5-9W, just to turn on the PSU, no load.

Pic1 Is the bigger one a standard ATX connector? According to specs they should have 1 purple wire but on the picture I can see at least 4 or they are using this color instead of red/orange? Pic2 Those white things are potentiometers for regulating voltages?Pic3 What does that button do?

Yes, Pic1 shows a standard ATX connector next to the small Dell one. For whatever reason, the PSU I cut this cable from used non-standard colors. For instance purple = orange = 3.3V. So I have to be careful and match the correct colors with the pinout of the ATX connector.

I'm assuming those are the voltage pots yes. But since I haven't turned it on yet I haven't been able to check. Although I don't expect I'll touch them at all.

Not sure what the button does. I was guessing a hard reset maybe.

lobuni wrote:

There is a dell dimension pin-out too available but this seems to have different wiring and this RM112 coloring seems closer to ATX specs.

Dell has used many a non-standard connector in the past. Your link is from a Dimension 8100 which is not the same. This one is still 24 pins just like ATX. But in a different order. And I think I counted one less (or more) 3.3V cable. But the important things are there. 12V, 5V, 3.3V, -12V, PS_ON, PS_OK, 5VSB. I don't think I'll run into any real issues. I also built an adapter for some older dell PSUs when they used to use the standard ATX connector but with the wires in a different order. At least now they seem to be using their own connectors to keep people from frying their motherboards.

I would have started soldering last night but noticed I was out of heat shrink. So I'm hitting the hardware store today. I've also made some marks on the ATX PSU case where I'm expecting to cut out to make this thing fit. It'll be sticking out the end as it's a good bit longer. Hopefully I'll have some tests to report on before the weekend is over.

I'm one of those much interested on the PSU The ATX cabling is a bummer, though in all but the strangest ITX cases the cable will anyway be too short, so some extra work is mandatory.
When you have time, could you check the unit's size and the fan's thickness?

Saw the other thread about this, looks like it'd be a pretty good little PSU. Non-standard ATX connector might be a deal-killer for most, though, it'd be a major pain to solder that up to a normal ATX. Can you find adapters online to mate a Dell ATX connector to standard? Would be a lot easier to just buy one of those than wire up a new connector.

Looks like you can get cables to adapt a regular power supply to a 24-pin mini ATX mobo, but I've yet to find anything that would allow one of these PSUs to be plugged into a standard mobo.

Soldering went well. Only connected one wire wrong and noticed very shortly after. (Grey wire to grey, instead of green. What was I thinking?) Everything seems to be working fine. Only odd thing is then every time I turn it on, it causes a ground fault protected socket to trigger. But it's in a different part of the house and the stuff plugged into the same outlet as the PSU is fine. Not sure how that's happening. Anyways, here's the result of my comparison.

Definitely better than both the picoPSU and Seasonic. 2W less at idle and 3W under load on this very low-powered system. Mind you the brick for the picoPSU is a 200W one from a shuttle SD11G5. There's no fan on it so must be pretty efficient. But as you can see, it's not any better really than the seasonic so maybe it's not so efficient at low loads. And the seasonic started to idle at 22W. But after stopping the cpu burn, it then was idling at 21W. Really neck and neck with the pico. PF was pretty low on the Dell. But not a huge deal at these levels and it was up to .9 by around 30W.

Here are a couple more pictures. First is half way through the wiring. Second is plugged into an old PC in case of any accidents. And last is next to a normal PSU case for size comparisons. The PSU itself is 3.25" x 2.5" x 8.25".

Is there a pinout diagram on the case? Or did you just match up the colors on the output wires of the Dell PSU to a standard 24 pin ATX connector? Dell makes quite a few high efficiency, low power PSUs actually, it's just too bad most of them dont follow ATX standards.

What are the dimensions of the projection? I believe the Dell RM112 will fit w/o modification into my Foxconn mini-ITX case, but the projection is the key. Also do you have a photo of the power plug/mounting end?

Is there a pinout diagram on the case? Or did you just match up the colors on the output wires of the Dell PSU to a standard 24 pin ATX connector? Dell makes quite a few high efficiency, low power PSUs actually, it's just too bad most of them dont follow ATX standards.

No pinout but the colors looked to match ATX and I checked a few of them on the board where it was labeled so I was pretty confident they were all correct.

Parappaman wrote:

Wow, that's some seriously high efficiency! That 3w translates to a 9% difference How's the fan at these loads?

Yeah, totally forgot to mention noise. The fan was surprisingly quiet at these loads. And there was only a small amount of clicking noise. I actually would probably be fine using it as is in most situations. There was a bit of coil whine and stuff. Not a terrible amount but with as quiet as the fan was, the coil whine was probably about at the same level. I want to try it out on a higher powered system to see if I can get it to ramp up at all and test efficiency at higher loads too.

Im doing some searching here and it appears the Dell PW116 is an equivalent to the RM112 according to 80plus. But the test sheet for the RM112 does not mention anything about the PW116. Anyone know how Dell labels these things? Would it be a safe assumption that the PW116 has the same high efficiency?

Generally saves around 10W across the board. I was a little leery running the pico on this system. But since it's just passing the 12V from the brick which is rated at 200W, I figured it would be okay. And it was. But it seemed to be loosing efficiency under the heavy load.

I was going to ask MikeC if they wanted to run this through their test bench before I started hacking it to pieces. But I forgot until after I already started. Opps. But here it is in all it's ATX glory. I've only tested it out on one system so far and nothing blew up. So I don't think I screwed anything up too bad. But I'm still going to be careful with it for a little while. Since the cables had to be routed out of the ATX case, I lost some length there. Especially on the mini-SATA power cable. I kept the whole bottom of the original case in tact and just cut the exhaust grill out except for one screw hole. I use this to hold it in place as you can see the screw at the bottom of the third picture. I then cut the other two parts so that they just reach inside the ATX case. The electrical tape there isn't to hold it in place but just to avoid the sharp edges from cutting the wires when putting it in. They do make the fit nice and tight though. There's a second screw you can see in the third picture that's holding the "reset" switch (or whatever it is) and LED. I had to put it somewhere and the wires for it are pretty short.

I've got an Enermax Enlobal fan in there. The initial fan voltage is 4.3V and isn't quite enough to start it up. Just a small push and it keeps going. I haven't put it in a powerful enough system yet to see when it would kick in. That'll be my next test. I did plug an ADDA low speed ball-bearing fan from a different PSU in and it started just fine. But was definitely not quiet enough.

Alright, final testing with this thing from me. I put it in my desktop PC which is in a mini-P180 case. It fit fine. The extra length part covered part of the bottom vent. But being that the case is on carpet, I don't think anything gets in that way anyways. I needed an ATX extension previously so no issues reaching that. The P4 cable even with the extension couldn't reach around the back so I had to go around the video card and over the motherboard. Could just get a longer extension. We'll see. Only needed one molex for the 5V Yate Loon fan on the front and one SATA for the Super Talent SSD right there next to the PSU. No cable length issues there. I did end up switching the fan for a Scythe S-Flex (1200rpm one) and it always starts and spins very slowly. Here's a couple pictures...

Compared to the Seasonic SS-350ET (80+ bronze) PSU, idle power went from 59W down to 53W AC and load power went from 144W to 138W AC.

I'm surprised this thread hasn't garnered more interest... I think this looks like an awesome solution over a pico psu for a relatively low power system. I'm looking to build such a system and would like to copy this idea. I have decent soldering skills, but would rather not have to solder if I can find an alternative. I found some adapters herethat look like they might work. BillyB, do any of those look right to you?

Thanks flyingsherpa. The HP mini connector looks like it might be the same thing. But it's going the wrong direction. It would need to be a mini to ATX not ATX to mini. Sure would be nice if if someone would sell that maybe with an adapter plate to let you screw the PSU into a normal case. Although it would be even nicer if someone actually make an ATX PSU based on the same design.

Ah yes, I noticed right after I posted that that the plug is male and not female. Oh well. Can you tell me if the mini connector has different gauge wire / pins than a normal ATX connector? I'm hoping I can just get a tool to pull the wires out of the mini one and plug them in to a normal one.

One more question: did you add those molex connectors? I'm just wondering what the psu originally came with... none of the pics I've found here or on ebay show all the stock connectors. I'm just trying to figure out how much modding I'd need to do on this thing.

Ah yes, I noticed right after I posted that that the plug is male and not female. Oh well. Can you tell me if the mini connector has different gauge wire / pins than a normal ATX connector? I'm hoping I can just get a tool to pull the wires out of the mini one and plug them in to a normal one.

Yes, the pins are definitely smaller than a normal ATX. Swapping would not work.

flyingsherpa wrote:

One more question: did you add those molex connectors? I'm just wondering what the psu originally came with... none of the pics I've found here or on ebay show all the stock connectors. I'm just trying to figure out how much modding I'd need to do on this thing.

Yes, I added the extra molex connectors. In my first picture I posted, you can see everything it came with originally which is just a single SATA and a single mini-SATA. I cut off the SATA and replaced it with a 2x SATA and 2x molex. I left the mini-SATA but it just barely makes it out of the back of the PSU.

Just received the modded Dell 80+ Gold you sent, BillyBuerger. Larry and I were just marveling at your handiwork. If the casing of the Dell was the same blue/gray of the FSP ATX12V casing you used instead of unpainted aluminum, we might think it's an odd form factor product from FSP!

Sweet, I'm currently in the process of almost exactly copying what Billy did. I've done all the soldering and am now trying to cram the RM112 into a regular ATX PSU case. Hope your review shows me that I'm not wasting my time

Just received the modded Dell 80+ Gold you sent, BillyBuerger. Larry and I were just marveling at your handiwork. If the casing of the Dell was the same blue/gray of the FSP ATX12V casing you used instead of unpainted aluminum, we might think it's an odd form factor product from FSP!

Hopefully, I'll have a chance to check it out soon.

Sweet, somehow I missed your post here and was wondering if you got it okay. Didn't seem to hit any problems with customs. Thanks for the compliments. Compared to some of my other attempts at modding things, this one did seem to come out pretty good.

There was no specific schema for wiring. I believe the Dell wire colors match normal PSU wires. So it's red-red, black-black, orange-orange, etc... As I mentioned, the only "issue" was that the orange wire count didn't match. So I had a couple of cases where two orange wires on one side connected to 1 orange wire on the other. Not a big deal. That and the PSU I got my 24pin ATX connector from used non-standard colors so I had to be careful there. But assuming you don't have this issue, there is no schema to post.

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